When using imaging devices for diagnostic purposes, clinicians often are looking for very subtle image features that can indicate the presence of disease. It is well known that brighter displays provide clinicians with the ability to see more subtle features as compared to darker displays having the same physical contrast. It is for this reason that medical displays in particular are typically designed to be as bright as possible with the best achievable contrast.
Typical medical displays are either transmissive or emissive. Transmissive displays, such as Liquid Crystal Displays (LCDs), utilize a backlight with one or more light sources, such as Cold Cathode Fluorescent Lamps (CCFLs), Light Emitting Diodes (LEDs) and the like, and a dedicated optical component, such as a liquid crystal layer, which may be combined with additional optical layers, e.g. polarizers. Because liquid crystals merely modulate and do not emit light, LCDs are considered transmissive displays. Unlike transmissive displays, emissive displays, e.g., organic light emitting diode (OLED) displays polymer light-emitting diode (PLED) displays or electroluminescent displays (ELDs), utilize materials that emit light.
Of course, it is known that higher luminance results in higher heat levels which speeds up degradation and decreases efficiency. And increasing the current (drive level) sent through the display (in case of an emissive display) or the backlight of the display (in case of a transmissive display), increases the rate of degradation. For example, if the backlight of a display with two layers (a backlight and an LC layer) is continuously driven to produce maximum luminance output, degradation will occur much more quickly as compared to the same backlight that is driven to produce a lower luminance output.
In certain circumstances, such as in clinical evaluation of patient images, it may be desirable for users of displays to examine specific features present in only part of an image. Accordingly, it may be desirable to provide a method for increasing the visibility of features in part of an image.